Electrical cables are widely used in telecommunications applications for the transmission of voice, video and data signals. Such cables typically include a conductive cable core surrounded by a jacket that provides mechanical strength and protection to the cable core. Polyvinyl chloride (“PVC”) is commonly used as a cable insulating and jacketing material because it is inexpensive and flexible, even at lower temperatures. However, PVC produces considerable amounts of smoke and releases toxic halogen compounds when it burns. To reduce the risk of fire propagating through a building's ductwork, safety codes often require that plenum-rated cables meet industry standards for low smoke generation and low flame spread. To successfully achieve a plenum rating, cables are constructed of materials that are more fire resistant and produce less smoke than traditional jacket materials. Various halogen-free polymers have also been employed, such as polyolefins. Due to their relatively low melting point, however, polyolefins still do not provide sufficient thermal protection. Furthermore, it is often necessary to employ a bromine-based flame retardant in polyolefin conduits to help improve resistivity to fire. Once again, the presence of a substantial amount of bromine in the conduit can still lead to the production of toxins at high temperatures.
As such, a need currently exists for a thermoplastic composition that is generally fire-resisting and also has a relatively high melting point so that it can be employed in an electrical conduit.